Kanelbulle release candidate 6.0.0a15

Bugfix. There was a subtle error in how the template sequence was chosen for the
pydna.design.circular_assembly_fragments in some situations. There were no tests for this
and there were also no effect on the final result.

What's Changed

• Issue 147 by @manulera in #150
• closes #154 by @manulera in #155

New Contributors

• @manulera made their first contribution in #150

Full Changelog: v6.0.0a4...v6.0.0a15